Problems organizing a struct in C

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Problems organizing a struct in C

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#1 by (0 votes)

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I'm having trouble organizing the data of a struct, the data is even organizing, but I always end up getting memory garbage in the first position, the others are organized normally without errors. The structure should be in descending order according to the given int struct of the struct.

    #include <stdio.h>
    #include <stdlib.h>
    #include <string.h>

   typedef struct concurso
  {
  char nome[30];
  int matri;
  int prov1;
  int prov2;
  int prov3;
}con;

typedef struct clasificados
{
  char n[30];
  int m;
  int pont;
}cla;

void ordena(con* co,int tam)
{
  cla *conc=(cla*)malloc(sizeof(cla)*tam);
  cla aux;
  int i,j=0;
  for(i=0;i<tam;i++)
  {
  if((co[i].prov1>40)&&(co[i].prov2>40)&&(co[i].prov3>40)&&(co[i].prov1+co[i].prov2+co[i].prov3>=150))
  {
    conc[j].pont=co[i].prov1+co[i].prov2+co[i].prov3;
    strcpy(conc[j].n,co[i].nome);
    conc[j].m=co[i].matri;
    j++;
  }
  }
//O PROBLEMA ESTA DAQUI PARA BAIXO, AQUI QUERO ORDENAR OS DADOS DA STRUCT CLASSIFCADOS, ATE QUE ORDENA, MAIS O PRIMEIRO ELEMENTO SAI COMO LIXO DE MEMORIA
    for( i=0; i<j; i++ )
    {
      if( conc[i].pont < conc[i+1].pont )
      {
        aux.pont = conc[i+1].pont;
        conc[i+1].pont = conc[i].pont;
        conc[i].pont = aux.pont;

        strcpy(aux.n,conc[i+1].n);
        strcpy(conc[i+1].n,conc[i].n);
        strcpy(conc[i].n, aux.n);

        aux.m = conc[i+1].m;
        conc[i+1].m = conc[i].m;
        conc[i].m = aux.m;
        i=-1;
      }
    }

    printf("\n\t\t------Classificados-------\n");
    printf("\nPOSICAO\t\tMATRICULA\tCANDIDATO\tNOTA\n");
    for( i=0; i<j; i++ )
    {
      printf("%d\t\t%d\t\t%s\t\t%3d\n",i+1,conc[i].m,conc[i].n,conc[i].pont);
    }
    free(conc);
}

int main()
{
  int i,j;
  int tam;
  printf("Digite o numero de candidatos: ");
  scanf("%d",&tam);
  con *c=(con*)malloc(sizeof(con)*tam);

  for(i=0;i<tam;i++)
  {
    printf("Digite o nome do candidato %d: ",i+1);
    scanf(" %[^\n]s",c[i].nome);

    printf("Digite a matricula do candidato %s: ",c[i].nome);
    scanf("%d",&c[i].matri);

    printf("Digite a nota 1 do candidato %s: ",c[i].nome);
    scanf("%d",&c[i].prov1);

    printf("Digite a nota 2 do candidato %s: ",c[i].nome);
    scanf("%d",&c[i].prov2);

    printf("Digite a nota 3 do candidato %s: ",c[i].nome);
    scanf("%d",&c[i].prov3);
  }
  ordena(c,tam);

  free(c);

 return 0;
}

c

asked by anonymous 11.10.2017 / 00:24

1 answer

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score 0 · Accepted Answer

Basically your error is in for , your for is as follows, for( i=0; i<j; i++ ) , this way when you make your vector at index i + 1 , when your for , arrive at last loop it will give buffer overflow, and populate the memory location belonging to your vector.

To fix this error, you just have to for you put, i < j - 1 , setting for( i=0; i<j-1; i++ ) .

Without further ado here is the complete answer:

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

typedef struct concurso
{
    char nome[30];
    int matri;
    int prov1;
    int prov2;
    int prov3;
} con;

typedef struct clasificados
{
    char n[30];
    int m;
    int pont;
} cla;

void ordena ( con* co, int tam )
{
    cla* conc = (cla*)malloc(tam * sizeof(cla));
    cla aux;
    register int i , j;

    for ( i = 0, j = 0 ; i < tam; ++i ) {
        if ( (co[i].prov1 > 40) && (co[i].prov2 > 40) && (co[i].prov3 > 40) && (co[i].prov1 + co[i].prov2 + co[i].prov3 >= 150) )
        {
            conc[j].pont = co[i].prov1 + co[i].prov2 + co[i].prov3;
            strcpy(conc[j].n, co[i].nome);
            conc[j].m = co[i].matri;

            ++j;
        }
    }

    /*  O PROBLEMA ESTA DAQUI PARA BAIXO,
        AQUI QUERO ORDENAR OS DADOS DA STRUCT CLASSIFCADOS,
        ATE QUE ORDENA, MAIS O PRIMEIRO ELEMENTO SAI COMO LIXO DE MEMORIA   */
    for ( i = 0; i < j - 1; ++i ) {
        if ( conc[i].pont < conc[i+1].pont )
        {
            aux.pont = conc[i+1].pont;
            conc[i+1].pont = conc[i].pont;
            conc[i].pont = aux.pont;

            strcpy(aux.n,conc[i+1].n);
            strcpy(conc[i+1].n,conc[i].n);
            strcpy(conc[i].n, aux.n);

            aux.m = conc[i+1].m;
            conc[i+1].m = conc[i].m;
            conc[i].m = aux.m;

            i = -1;
        }
    }

    printf("\n\t\t------Classificados-------\n");
    printf("\nPOSICAO\t\tMATRICULA\tCANDIDATO\tNOTA\n");

    for ( i = 0; i < j; ++i )
        printf("%i\t\t%i\t\t%s\t\t%3i\n", i+1, conc[i].m, conc[i].n, conc[i].pont);

    free(conc);
}

int main()
{
    register int i,j;
    int tam;
    con* c;

    printf("Digite o numero de candidatos: ");
    scanf(" %i", &tam);

    c = (con*)malloc(tam * sizeof(con));

    for ( i = 0; i < tam; ++i ) {
        printf("Digite o nome do candidato %d: ", i+1);
        scanf(" %[^\n]s", c[i].nome);

        printf("Digite a matricula do candidato %s: ", c[i].nome);
        scanf(" %i", &c[i].matri);

        printf("Digite a nota 1 do candidato %s: ", c[i].nome);
        scanf(" %i", &c[i].prov1);

        printf("Digite a nota 2 do candidato %s: ", c[i].nome);
        scanf(" %i", &c[i].prov2);

        printf("Digite a nota 3 do candidato %s: ", c[i].nome);
        scanf(" %i", &c[i].prov3);
    }

    ordena(c,tam);

    free(c);

    return 0;
}

I hope I have helped;).